A microcosm study on persulfate oxidation combined with enhanced bioremediation to remove dissolved BTEX in gasoline-contaminated groundwater

Integration of microbial reductive dehalogenation with persulfate activation and oxidation (Bio-RD-PAO) for complete attenuation of organohalides

“…Consequently, the comparatively longer lifetime, higher reactivity and lower cost of persulfate-AOP relative to H 2 O 2 -AOP enable the former method to be an optimal option for the remediation of lowly-halogenated organohalides at in situ remediation sites. Consequently, PAO may complement the OHRB-mediated microbial reductive dehalogenation (Bio-RD) process for extensive cleanup of pollutants (Nam et al, 2001;Hrapovic et al, 2005;Kulik et al, 2006;Ndjou'ou et al, 2006;Sahl and Munakata-Marr, 2006;Lu et al, 2010;Venny et al, 2012;Sutton et al, 2014a;Sutton et al, 2014b;Němeček et al, 2019;Xia et al, 2020). Nonetheless, these studies employed in situ chemical oxidation (ISCO) as a pretreatment process to enhance the bioavailability and biodegradability of pollutants.…”

“…Previous studies have investigated the impacts of chemical oxidation as a pretreatment method to enhance both the degradability and availability of organohalides for subsequent biological conversion processes (Nam et al, 2001;Hrapovic et al, 2005;Kulik et al, 2006;Ndjou'ou et al, 2006;Sahl and Munakata-Marr, 2006;Lu et al, 2010;Venny et al, 2012;Sutton et al, 2014a). Results have shown that aggressive oxidation and deleterious effects of chemical oxidants significantly decrease the amount of biomass and change the composition of the microbial community (Sutton et al, 2014b;Němeček et al, 2019;Xia et al, 2020). Consequently, chemical pretreatments with oxidants may not improve the overall remediation efficiency.…”

“…Therefore, it is challenging to alleviate the side impacts of persulfate oxidation on microbial communities and their activities. Although it has been reported that the impacts of persulfate activation oxidation on bioremediation are reduced by optimizing the molar ratio of persulfate and pollutants, as well as of persulfate and activators (Xia et al, 2020), the specific mechanism is still unclear.…”

Biogeochemical Alteration of an Aquifer Soil during In Situ Chemical Oxidation by Hydrogen Peroxide and Peroxymonosulfate

“…Consequently, studies on the effect of ISCO on in situ bioremediation efficiency involve some controversy . According to some studies, the coupling of ISCO and bioremediation is advantageous because this reduces the mass of the toxic chemicals and/or converts some to more biodegradable compounds . Conversely, other works report undesired effects of ISCO on the indigenous microbial activity, population, and community structure − due to oxidative stress and changes in the pH and redox conditions.…”

“…14 According to some studies, the coupling of ISCO and bioremediation is advantageous because this reduces the mass of the toxic chemicals and/or converts some to more biodegradable compounds. 15 Conversely, other works report undesired effects of ISCO on the indigenous microbial activity, population, and community structure 16−18 due to oxidative stress and changes in the pH and redox conditions. These discrepancies are probably related to the oxidant concentrations and type.…”